Detection of light emitted in the infrared (IR) wavelength region of the spectrum (e.g. mid-infrared wavelengths from about 2 micrometers (μm) to about 8 μm (mid-IR) and long/low-wavelength infrared wavelengths (LWIR) from about 8 μm to about 15 μm) may have wide spread applications that include missile defense, night vision imaging for security and soldiers, and trace gas sensing imaging, such as chemical detection and explosive detection. Current detection technologies with high sensitivity are typically based on semiconductor photodetectors. In the past, many semiconductor material systems have been studied and progress has been made in developing semiconductor photodetectors. For instance, several industry approaches for semiconductor material photodetectors include Mercury-Cadmium-Telluride (HgCdTe) based photodetectors (MCT photodetectors), Indium-Antimonide (InSb) based photodetectors, and quantum well infrared photodetectors (QWIPs). Although progress has been made, the semiconductor photodetectors generally operate at relatively low temperatures in conjunction with cooling systems.
Among the different semiconductor photodetectors, typically MCT is used for mid-IR Focal Plane Array (FPA) applications. For example, MCT may be produced by using molecular beam epitaxy (MBE) on Cadmium-Zinc-Telluride (CdZnTe) substrates. However, the CdZnTe substrates are often relatively costly, brittle and of relatively small size. As a result, the semiconductor industry is attempting to transfer the growth and processes of MCT to alternative substrates, such as Silicon (Si). Transferring the growth and processes of MCT to a Si substrate may encounter problems because of the about 19% lattice mismatch and about 100% thermal mismatch that may cause deleterious effects on the final FPA. To date, at the FPA level, median sensitivity and noise characteristics are often equivalent to CdZnTe-based arrays, but unfortunately, array operability can be relatively low. In addition, because of defect related tunneling in MCT, FPAs using MCT produce undesired levels of electronic noise and non-uniformities. The non-uniformities may be corrected with algorithms that employ powerful signal processors. Moreover, cooling is required for MCT detectors to achieve a relatively high sensitivity. Thus, MCT may have a relatively high cost of MCT FPAs, suffer from relatively low reliability, and face numerous manufacturing challenges.